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Find the z-score for specific left-tail probabilities:

(a) When the area under the standard normal curve to the left is 0.9947.
(b) When the area under the standard normal curve to the left is 0.7675.

User Phact
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1 Answer

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Final answer:

To find the z-scores for left-tail probabilities of 0.9947 and 0.7675 on a standard normal distribution, one would use a z-table or calculator function such as invNorm to determine the corresponding z-scores for the probabilities provided.

Step-by-step explanation:

The question relates to finding the z-score for a given left-tail probability on a standard normal distribution. The z-score corresponds to how many standard deviations away from the mean a point is on this distribution. For a left-tail probability of 0.9947, one would use a z-table or calculator to find the z-score that has 99.47% of the area under the curve to its left. For a probability of 0.7675, the procedure is similar; locate the z-score that corresponds to 76.75% of the area under the curve to its left.

To find the z-score corresponding to the left-tail probability of 0.9947, we can use a probability table for the standard normal distribution or software/calculator with the function invNorm(0.9947). Similarly, to find the z-score for a left-tail probability of 0.7675, use the function invNorm(0.7675).

These z-scores are used to determine how an individual score relates to the distribution as a whole. They can be used for calculating probabilities, determining percentiles, and testing hypotheses in statistics.

User Vishal Biyani
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